نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناسی ارشد، مهندسی مکانیک، دانشگاه صنعتی اصفهان، اصفهان.

2 استادیار، مهندسی مکانیک، دانشگاه صنعتی اصفهان، اصفهان.

3 استاد، مهندسی مکانیک، دانشگاه صنعتی اصفهان، اصفها ن.

10.22068/jstc.2022.547872.1769

چکیده

ایجاد پوشش ها با حداقل مولفه های مواد و مراحل تولید یکی از چالش های امروز در تهیه فیلم های نانوکامپوزیتی آب گریز است. هدف از این تحقیق تهیه پوشش نانوکامپوزیت پایه پلیمری آب گریز و بررسی ارتباط بین خواص آب گریزی، میکروساختار، درصد فاز افزودنی و انرژی آزاد سطح آن می باشد. بدین منظور، از نانوذرات سیلیکا اصلاح شده با هگزامتیل دی سیلازان به عنوان فاز افزودنی و اتیلن وینیل استات به عنوان زمینه و از تولوئن به عنوان حلال استفاده شد. غلظت پلیمر/ حلال با غلظت 3% به عنوان غلظت بهینه برای تشکیل فیلم انتخاب شد. مقادیر 10%، 20% و 30% وزنی نانو ذرات به محلول اضافه شد و از روش پاشش به دلیل یک مرحله ای بودن استفاده شد. نتایج نشان داد پوشش پر شده با 30 درصد نانوسیلیکا دارای حفره ها با ساختاری متخلخل و شبکه ای بوده که موافق با پیش بینی مدل انرژی سطح کیسی- بکستر بود. پوشش های نانوکامپوزیتی با 30% نانوسیلیکا منجر به زاویه تماس استاتیکی 121 درجه با 34% افزایش نسبت به سطح اتیلن وینیل استات خالص و زاویه غلتش 8 درجه با 90% کاهش نسبت به نمونه های 10 درصد وزنی شدند. انرژی آزاد سطح از سه تئوری اوونز-وندت، فوکس و ون اوس بررسی شد که بر خلاف تئوری ون اوس تئوری های فوکس و اوونز-وندت نشان دادند که با افزایش غلظت نانو مواد، جزء قطبی انرژی آزاد سطح پوشش کاهش یافته که موید افزایش زوایای تماس تخمین زده شده در این مطالعه بود.

کلیدواژه‌ها

عنوان مقاله [English]

Self-cleaning properties and free surface energy of ethylene vinyl acetate (EVA) nanocomposite coatings reinforced with silica nanoparticles

نویسندگان [English]

  • Mehdi Hasan Zadeh 1
  • Mehdi Karevan 2
  • Ahmad Reza Pishevar 3

1 Mechanical Engineering Department, Isfahan University of Technology, Isfahan, Iran.

2 Mechanical Engineering Department, Isfahan University of Technology, Isfahan, Iran.

3 Mechanical Engineering Department, Isfahan University of Technology, Isfahan, Iran.

چکیده [English]

The preparation of coatings involving the least material components and fabrication route is one of the today’s challenges in the development of hydrophobic nanocomposite films. This study aims at the fabrication of a hydrophobic polymer nanocomposite coating and the evaluation of the interplays amongst hydrophobicity, microstructure, fillers loading and free surface energy of the coatings. To achieve this, hexamethyldisilazane functionalized nano-silica as the filler and ethylene vinyl acetate (EVA) as the matrix were used. Toluene was used as the solvent. The concentration of 3% was employed as the optimized solvent ratio to create polymer film. The loadings of 10,20 and 30 wt% of nanomaterials were added into the solvent followed by a spray technique due to its single step approach. The analyses showed the coating filled with 30 wt% of nano-silica resulted in a porous interconnected structure, in good agreement with the Cassie-Baxter surface energy model. The 30 wt% nano-silica nanocomposite coatings resulted in a static water angle of ~121 ͦθ exhibiting a 34% increase with respect to that in the case of pure EVA and a sliding angle of 8 ͦθ with 90% reduction compared to the 10 wt% filled coatings due to the high surface roughness. Three surface energy models of Fowkes, Owens-Wendt and Van Oss were utilized were employed through which, unlike from the Van Oss model, the Fowkes and Owens-Wendt models exhibited that with the addition of fillers, the polar component of the free surface energy decreases confirming the increase in the estimated water angle contact.

کلیدواژه‌ها [English]

  • Self-cleaning
  • Nano silica
  • surface energy
  • Hydrophobicity
  • Nanocompoiste coating
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